diff i.d help

[frenchi]

can anyone tell me about this diff ,i have two tags on back ithink its lsd,as both drive shafts turn same the same way,tag 1,,BPL,second,,46-13,this is being fitted to an overdrive box then onto a 4.2,also when diff is out on bench you can feel cogs lifting in and out as you turn but the other way its clear,but once its all in cradle and drive shafts on only moves one way the other is fixed any help in i,d and problem,much appreciated,thanks fellers

[Heuer]

46/13 = 3.54 ratio